Hot-blast stove



Nov. 1, 1927. 1,647,570

. F. E. KUNG EGT BLAST STOYE Filed May 15, 1926 FEED E /Q /N PatentedNov. `1., 1927.

UNITED lSTATES FRED E. KLING, OF YOUNGSTOWN, OHIO.

Hor-BLAST srovn.

'application med nay 15,

This invention relates to hot blast stoves and more particularly tocontinuous hot blast stoves, and has for one of its objects-the'provision of a continuous hot` blast stove having a materially higherefficiency than hot blast stoves heretofore constructed.

f Another object is to provide a stove of the class described which willhave a long life due toits novel construction.

. A further object is to provide a stove having novel means forpermitting expansion of the parts due to the high temperatures.

A still further obj ect is to provide a stove having the novelconstruction, design and combination of parts hereinafter described andillustrated in the accompanyingldrawings.

In the drawings: y A C Figure 1 is a vertical section through a stoveconstructed in accordance with this inv vention. Figure 2 is a sectionalplan of the stove. Figure 3 is a vertical section on the line III-III ofFigure 1.

Referring more particularly to the drawings, the numeral 2 designatesthe stove as a whole, which is composedof a combustion chamber 3 and aheat exchanging chamber A gas or other fuel burner 5 is mounted 1n theend wall 5a of the stove and enters the 6 counter-current to theproducts of combuscombustion'chamber 3. The burner 5 is preferablyfa gasburner adapted to burn dry cleaned blast furnace gas. o l

The combustion chamber 3 opens into the heat exchanging chamber 4, whichlast namedv chamber is provided with a flue or stack opening 4a at theopposite end from the combustion chamber so that the products ofcombustion must flow through the heat exchanging chamber in order topass to the stack.

A system of air blast pipes 6 are mounted in the heat exchanging chamber4. `The pipes 6 enter the chamber 4 at its end farthest from thecombustionl chamber 3 and are coiled upwardly and downwardly through thechamber 4 and exit through the opposite end of the heat exchangingchamber above the combustion chamber. The several coils of the pipes 6are inclined slightly from the vertical so as to form supports for bailewalls 7 which are arranged infront of each of the coils of pipe and reston the pipe.

The inclination ofthe coils of pipes 6 is as slight as practical inorder to support the baille walls and at the same time reduce the 192s.serial No. 109,452.

bending strains in the pipes to a minimum. 4An additional baffle wall 7.is arranged under the exit end of the pipes 6 to prevent the productsof combustion impinging di- .The cold `blast is adapted to enter thepipes 6 from a main 8 through a manifold 9 and toJiiow through saidpipes counter-cur- 'rectly against the .pipes as they leave thecombustion chamber. i

pipes may be four inches in diameter while the exit end will be sixinches ormore in diameter, and the intermediate portion will of thesesections will be preferably welded tothe preceding section so as to makea tight Joint.

By passing the blast air through the pipes tion passing through thechamber 4, the

' products of combustion contact with the portion of the pipes 6containing the low temperature air, resulting in high efficiency ofutilization of heat and consequently low consumption of gas or fuel.

The portion of the pipes 6 in the hot zone of the stove that is nearestthe combustion chamber 3 is preferably made of a chrome steel alloy soas to withstand the high temperatures to which they are subjectedwithout progressive oxidation, while the remainder of the pipes 6located in the cooler zone of the'stove that is farthest from thecombustion chamber 3 maybe composed of ordinary standard or commercialsteel.

The pipes 6, due to the'temperatures to which they are subjected, willhave considerable expansion.k Therefore, the coils of the pipes 6 areterminated short ofthe top wall of the chamber 4 so: as to permit themto eX- pand upwardly, `while the lower ends of the coils are supportedor seated on the bottom wall of the chamber.

The upper ends of the coils of pipes 6 are y each provided with guiderods 14 which project upwardly into suitable recesses 15 1n the top wallof the stove to support the'upper ends of the coils and permit freeexpansion thereof.

The pipes 6 in the hot zone or nearest the` combustion chamber 3 will besubjected to the highest temperatures and will, therefore, have ,thegreatest expansion, whereby the coils nearest they combustion chamberwill tend to lift the adjoining coils from the bot-J tom wall of thestove while the coils nearest the' combustion chamber remain seated onthe bottom wall. To compensate for this unequalv expansion, and toprevent undue load or stresses on the pipes due to the unequalexpansion, the coils of the plpe's 6 1u the cooler zone` or farthestfrom the combustion chamber 3, are provided with plunger rods 16 whichextend downwardly into a recess 17 and yare engaged by springs 18 whichserve to normally force the cool pipe coils, and thereby prevent warpingof the pipe coils due to unequal expansion.

The temperature of the air blast in stoves of this classl can beautomatically controlled by standard thermostat gas control apparatusoperable by the temperature of the hot blast and adapted to regulate theflow of gas to the burner 5. The thermostat mechanism is not shown,since any of the several standard thermostatically controlled regulatorsmay be used.

The efficiency of a hot blast stove of this class is materially higherthan stoves heretofore in use, since the temperaturel ofthel Awastegases or products of combustion leaving the heat exchanging chamber canbe kept at approximately five hundred degrees Fahrenheit, due to thewaste gases being in contact with the pipes 6 carrying air atapproximately two hundred degrees Fahrenheit prior to their exit to thestack. The efficiency of this stove will also be higher due to itsmaterially decreased radiating surface over stoves heretofore in use.

The present stove will require considerably less labor due to it beingcapable of automatic control, and due to the fact the chimney and othervalves are eliminated thereby reducing the parts liable to give trouble.

The present stove will not clog with dustsince the dust can be blown offthe pipes 6 with soot-blowers during the operation of the stove, therebypermitting constant high eliiciency.

The above and many other advantages will be readily apparent to thoseskilled in the art.

While I have shown and described one specific embodiment of myinvention, it will be understood that I do not wish to be limitedthereto since various modiications may be made without departing fromthe scope of my invention as deined inthe appended claims. 4

I claim:

1. A continuous hot blast stove comprising a combustion chamber, and aheat .exchanging chamber through which the products of combustion passfrom esaid combustion chamber, a plurality of metallic pipes coiledupwardly and downwardly through said 'heatexchanging chamber, the coilsof said pipes being inclined slightly from the vertical, baffle wallsalong each of said coils of pipes, said baile Walls being alternatelyspaced from the bottom and top walls of said heat exchan ing chamber tocause the products of com ustion to travel along all of said pipes,means for permitting said coils of pipe to expand upwardly, and meansfor compensating for the greater expansion of the pipes closest to saidcombustion chamber over the pipes farthest from said combustion chamber.

2. A continuous hot blast stove comprising a combustion chamber, and aheat exchanging chamber through which the products of combustion passfrom said combustion chamber, a plurality of metallic pipes coiledupwardly and downwardly through saidy heat exchanging chamber, the coils,0f said pipes being inclined slightly from the vertical,baille wallsalong each of said coils of pipes, said baille walls being alternatelyspaced from the bottom and top walls .of said heat exchanging chamber tocause 'the products of combustion to travel along all of said pipes, andmeansfor permitting said coils of pipe to expand upwardly. u

3. In a hot blast stove having a heat exchanging chamber,` a pluralityof air blast pipes coiled upwardly and downwardly through said chamber,said coils of said pipes terminating short of the top wall of saidchamber, and guide rods on the upper ends of said coils of pipe andmounted in recesses in the top wall of said chamber so as to supportsaid coils and permit expansion of said pipe.`

4. In a hot blast stove having a heat exchanging chamber, a combustionchamber communicating with the heat exchanging chamber at one endthereof and a lue communicating with said heat exchanging cha-mber atthe other end thereof so that the products of combustion will pass fromsaid combustion chamber through said heat exchanging chamber from end toend thereof, a plurality of air blast pipes coiled upwardly anddownwardly through said heat exchanging chamber, said coils of pipesterminating short of the 'top wall of said heat exchanging chamber,guide rods projecting from the upper ends of said coils of pipe andextending into recesses inthe top wall of said heat exchanging chamber,said coils of pipes adjacent said combustion chamber being adapted tohave a greater expansion than the pipe coils farther from saidcombustion hembalance the weight of said cooler coils and ber dueto thegreater heat of the products thereby compensate for the unequal expanofcombustion whereby said coils of pipes sion and prevent breakage of saidpipes. 10 having the least. expansion will be lifted In testimonywhereof, I have hereunto 5 from their seats,v and spring supports forsigned my naine.

supporting the lower ends of the coils of i pipes havlng the lesserexpansion adapted to v FRED E. KLING.

